When comparing MacVim vs Spacemacs, the Slant community recommends Spacemacs for most people. In the question“What are the best programming text editors?”Spacemacs is ranked 5th while MacVim is ranked 15th. The most important reason people chose Spacemacs is:

Spacemacs combines the Emacs platform (with the full power of the Emacs plugin ecosystem) and the Vi keybindings (via EViL), all in the same box.

OS X input methods

Pro

Extensive community support

Pro

Automatic font substitution

In cases of a selected font missing certain characters, MacVim will find a font that has that character.

Pro

Vimtutor teaches the basics of Vim in 30 minutes

Vimtutor is an excellent interactive tutorial for people with no prior experience of Vim. It's bundled with Vim and takes about 30 minutes to complete.

Pro

Everything is a mnemonic

Vim associates keys with words. For example, d is for "delete" and w is for "word". To perform an action you string together letters. Thus, to delete a word, press dw.

This way it's possible to abstract a large amount of functionality that Vim provides in an intuitive way.

Pro

Enables effective keyboard-driven editing due to its modal nature

Interaction with Vim is centered around several modes. Each mode has a different purpose and switching between them changes behaviour and keybindings. There are 12 modes in total (six basic modes and six variations on basic modes) and four of them are used commonly.

Insert mode is for entering text. This mode most resembles traditional text entry in most editors.

Normal mode (the default) is entered by hitting ESC and converts all keybindings to center around movement within the file, search, pane selection, etc.

Command mode is entered by hitting ":" in Normal mode and allows you to execute Vim commands and scripts similar in fashion to a shell.

Visual mode is for selecting lines, blocks, and characters of code.

Modes allow separating concerns between various tasks and reusing keys for different kinds of functionality. As a result, the workflow becomes more efficient.

Pro

Multi-byte support

Permits writing characters that don't fit in one byte, most notably logograms (for writing in languages such as Japanese, Chinese, and Korean) and Unicode characters.

Pro

Combines the best parts of Vi and Emacs

Spacemacs combines the Emacs platform (with the full power of the Emacs plugin ecosystem) and the Vi keybindings (via EViL), all in the same box.

Pro

Simple but powerful configuration architecture

At the heart of Spacemacs, the configuration layers group packages configuration into semantic units that can be toggled on and off. The architecture is simple but powerful, allowing the user to easily manage configuration dependencies between hundreds of packages.

Pro

Above average documentation quality

Documentation is mandatory for each new configuration layer and can be accessed directly within the editor in Org format.

Pro

Community-driven configuration

Spacemacs is the biggest community-driven Emacs starter-kit.

Pro

Cross-platform

Emacs runs on Gnu/Linux, Mac OS X, and Windows.

Pro

Great support from the community

The community surrounding Spacemacs is very active and there is a welcoming gitter chat for users to ask questions.

Pro

Completely configured out of the box

Stuff like version control, file management, good default theme are all configured out of the box.

Pro

Mnemonic and consistent keybindings

Space-lead key bindings are organized in mnemonic namespaces. For instance, buffer actions are under SPC b, file actions are under SPC f, project actions are under SPC p, search actions are under SPC s, and so on. Keybindings are consistent across the whole distribution thanks to a set of conventions.

Pro

Gradual learning curve

Evil package is a first class citizen and Spacemacs embraces it from day one. Evil package allows Vim users to be productive very quickly while still allowing regular Emacs users to use Spacemacs.

Pro

Lowers the risk of RSI by using the spacebar as leader

Spacemacs got its name from the fact that it is uses the space bar as a default leader key. The key was chosen because it is easy to press and to hopefully lower the risk of RSI.

Pro

Fast-paced development

New functionalities and fixes are added to Spacemacs every day, while release cycles are short.

Pro

Can be controlled fully with the keyboard

There's no need to reach for the mouse again since Spacemacs can be fully controlled with keyboard.

Pro

Manage many code bases easily

Pro

Remote file editing

Files can be edited in Spacemacs remotely.

Pro

Great note-taking and agenda "app" built-in

Allows for great organization applications that can be saved in future-proof format, plain text, can be integrated with LaTeX, markdown, HTML, Literate Programming and be committed to source control.

Pro

Offers a number of practical features

Spacemacs has some great features for taking notes, tracking to-do lists, and tracking time.

Pro

Manage R files easily

Pro

Great CFEngine support

Cons

Con

Slow when opening files with very long lines

A lot of very long lines can make MacVim take up to a minute to open, where a few other editors take only a few seconds to load the same file.

Con

Difficult learning curve

MacVim after all is still Vim, and with that comes the complexity that Vim brings and the difficult learning curve that needs to be overcome.

Con

Can be quite glitchy at times

Spacemacs combines many packages from many different authors that were never designed to work together. Sometimes they interact in unexpected ways, and things randomly break as one package interferes with another's features. This combined with delayed auto-loading of packages in unpredictable order, different modes for different file types, frequent package updates, and necessary customization by selection of layers and packages, can make these glitches hard to reproduce. It takes a lot of emacs know-how to fix these problems. Fortunately there is a very active community willing to help with these problems, but it might take a while.

Con

Slow startup time

Although configuration is heavily loaded, the starting time of Spacemacs is usually between two and five seconds. Emacs can be run as a daemon though which reduces the client's startup time to a few milliseconds.

Con

Functionality layers of complicated configuration

To configure Spacemacs, settings for Emacs/Evil/Spacemacs may need editing. It's not always clear which need to be changed or how to change settings globally: sometimes hooks are needed, other times Spacemacs provides options.

Con

High CPU and unresponsive at times

There are occasions when Spacemacs would suddenly consume a LOT of CPU and then other times would become completely unresponsive. This instability took place only 6 months or so ago. Restarting Spacemacs can fix it for a while but perhaps this issue is already fixed in newer versions.

Con

Complex learning difficulty

You must be familiar with either Vim or Emacs. In addition, you should be familiar with the unique features of Spacemacs. The Layer concept of replacing Emacs settings is still difficult and abstract compared to modern editors.